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    <title>ShellCheck: SC1106 – In arithmetic contexts, use `<` instead of `-lt`</title>
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    <h1>SC1106 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC1106">See this page on GitHub</a>
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    <h2 id="in-arithmetic-contexts-use--instead-of--lt">In arithmetic
contexts, use <code>&lt;</code> instead of <code>-lt</code></h2>
<p>Similarly, <code>&gt;</code> instead of <code>-gt</code>,
<code>&lt;=</code> instead of <code>-le</code>, <code>&gt;=</code>
instead of <code>-ge</code>, <code>==</code> instead of
<code>-eq</code>, <code>!=</code> instead of <code>-ne</code>.</p>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC1106.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="cf">if</span> <span class="kw">((</span> <span class="dv">2</span> <span class="op">-</span><span class="va">lt</span> <span class="dv">3</span> <span class="kw">))</span></span>
<span id="cb1-2"><a href="SC1106.html#cb1-2" aria-hidden="true" tabindex="-1"></a><span class="cf">then</span></span>
<span id="cb1-3"><a href="SC1106.html#cb1-3" aria-hidden="true" tabindex="-1"></a>  <span class="bu">echo</span> <span class="st">&quot;True&quot;</span></span>
<span id="cb1-4"><a href="SC1106.html#cb1-4" aria-hidden="true" tabindex="-1"></a><span class="cf">fi</span></span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC1106.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="cf">if</span> <span class="kw">((</span> <span class="dv">2</span> <span class="op">&lt;</span> <span class="dv">3</span> <span class="kw">))</span></span>
<span id="cb2-2"><a href="SC1106.html#cb2-2" aria-hidden="true" tabindex="-1"></a><span class="cf">then</span></span>
<span id="cb2-3"><a href="SC1106.html#cb2-3" aria-hidden="true" tabindex="-1"></a>  <span class="bu">echo</span> <span class="st">&quot;True&quot;</span></span>
<span id="cb2-4"><a href="SC1106.html#cb2-4" aria-hidden="true" tabindex="-1"></a><span class="cf">fi</span></span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p>The comparators <code>-lt</code>, <code>-ge</code>, <code>-eq</code>
and friends are flags for the <code>test</code> command aka
<code>[</code>. You are instead using it in an arithmetic context, such
as <code>(( .. ))</code> or <code>$(( .. ))</code>, where you should be
using <code>&lt;</code>, <code>&gt;=</code>, <code>==</code> etc
instead.</p>
<p>In arithmetic contexts, <code>-lt</code> is simply interpreted as
"subtract the value of <code>$lt</code>", which is clearly not the
intention.</p>
<h3 id="exceptions">Exceptions:</h3>
<p>If you do want to subtract <code>$lt</code> you can add a space to
make this clear to ShellCheck: <code>echo $((3 - lt))</code></p>
<h3 id="related-resources">Related resources:</h3>
<ul>
<li>Help by adding links to BashFAQ, StackOverflow, man pages, POSIX,
etc!</li>
</ul>
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